Client                              Server
              ----------                          ----------
  1)  --------------------  TCP Connection  -------------------
      (IP_I:Port_I  -> IP_R:Port_R)
      TcpSyn                   ------->
                               <-------              TcpSyn,Ack
      TcpAck                   ------->
  2)  ---------------------  TLS Session  ---------------------
      ClientHello              ------->
                                                    ServerHello
                                          {EncryptedExtensions}
                               <-------              {Finished}
      {Finished}               ------->
  3)  ---------------------- Stream Prefix --------------------
      "IKETCP"                 ------->
  4)  <---------------------> IKE/ESP Flow <------------------>